2010 Outback ABS problem?

I have a question about the antilock braking system on my 2010 Outback 2.5i Premium CVT. I have owned several Hondas with antilock brakes so I am familiar with how the system is supposed to work. However, when I try to stop the Outback on a slick surface and the ABS activates, the there is considerably more noise and rough feel than I am used to. It is a little hard to separate what I hear from what I feel through the brake pedal, but the engaging and disengaging of the brakes is seems much slower and rougher than on the Honda system.

I have only activated the Outback's ABS at relatively slow speeds, but the system does keep the car straight during braking. However, when I observe the wheels from outside the car during a skid, it is clear that the wheels lock and unlock more slowly than my Accord. I understand that antilock brake systems from different manufacturers may feel and perform somewhat differently, but in this case the difference is substantial.

So my question is, does it sound like the Outback's ABS is performing as it is supposed to, or is the much rougher feel an indication that there is a problem developing? I took the car in to have it checked, but the road conditions were dry so I doubt that the mechanic was able to do much other than look for error codes. No problem was found.

Comments

"However, when I observe the wheels from outside the car during a skid, it is clear that the wheels lock and unlock more slowly than my Accord."

So you watched your Accord's wheels lock up from the outside too? Under the exact same conditions at the same speed?

I'd be willing to bet this is a case of a difference between expectations and reality to the point where you are looking too hard for something to be wrong.

The visual observation of the wheels locking and unlocking will vary relative to the slickness of the surface the tire is slipping on and the speed at which you are going. Your visual observation is not an indication of malfunction.

The ABS system is computer controlled, has sensors at each wheel, and performs a diagnostic test every time you start the car. If there was a problem, you'd have a red ABS light on your display.

The sensation of ABS can be a strong vibration feeling in your foot and a chattering sound, and does vary from make to make in implementation and feel.

So I really doubt there is a problem with your ABS.

Nevertheless, better safe than sorry. If you're really concerned, stick with your gut and have your dealer continue to try to reproduce.

Oh, one other thing. Per section 7-25 of your user manual, ABS does not engage below 6 MPH. (Presumably to allow shorter stops on ice and gravel at very low speeds). This is common across all manufacturers, IIRC.

My point is, what you observed as a very slow locking and unlocking when watching your car may not have been ABS, but rather the actual tires gaining and losing traction while braking on whatever slick surface your were testing them on.

I've observed this on snow, where the crunching sound of the snow being compacted under my tires while braking can mimic the feel/sound of ABS.

So, like I said in my previous post, you may just be looking too hard to find a problem.

The comparison between the Outback and the Accord wasn't under optimal conditions because we did it in a partially snow-covered parking lot with a relatively short distance to accelerate and brake, but in both cars the ABS definitely activated. My son and I took turns driving both cars, so I had the opportunity to observe both inside and outside the vehicle. When I was watching the locking and unlocking of the wheels from outside the car I can't swear that the speeds were identical, but they were both in the 15-20 mph range.

The Honda system definitely sounds different as there is a distinct hum or buzz when the system activates that is reduced or absent in the Outback. In the Outback (at least in mine) it feels like the brake is being applied and released at a lower frequency with a harsher, more mechanical feel. This is consistent with my observation from outside the car, but I can't really quantify the difference. They may both be proper activation of slightly different systems. All I know is that after 10 years of driving Hondas, the feel of the Subaru system is different enough that I wish I could get confirmation that it is performing as designed.

I did the comparative testing while on a trip in Colorado (the Outback performed admirably in the mountains). Now that I am out of snow country, getting reliable road conditions to test the ABS may be difficult. This is why I am asking for other people's experience to see if there is a good reason to push the issue with the service department.

The way you describe your ABS performance sounds exactly the way all 5 of our Foresters have acted. It is definitely different than the way my Tundra does it.

I think what you have is normal and as Elliot said it is just the different implementation of the manufacturers. I also have to say that the first time it happened on my first Forester it made me sit up and wonder if it was normal because of the feel and noise, but since all 5 have performed the exact same way I don't think about it anymore.